Physical activity levels, pulmonary function, and MRI in children born extremely preterm: A comparison between children with and without bronchopulmonary dysplasia.

INTRODUCTION: Children with a history of bronchopulmonary dysplasia (BPD) may have lower physical activity levels, but evidence to date is mixed. This study compared physical activity levels between children born extremely preterm with and without history of BPD, and examined their associations with pulmonary magnetic resonance imaging (MRI) and pulmonary function test (PFT) indices. METHODS: This multicentre cross-sectional study included children aged 7-9 years born extremely preterm, with and without BPD. Children wore a pedometer for 1 week, then completed the Physical Activity Questionnaire (PAQ), pulmonary MRI, and PFT. Spearman correlations and multivariable linear regression modeling were performed. RESULTS: Of 45 children, 28 had a history of moderate-severe BPD. There were no differences in any physical activity outcomes by BPD status. Higher average daily step count and higher average daily moderate-to-vigorous physical activity (MVPA) were each correlated with greater forced vital capacity (r = 0.41 and 0.58), greater MRI lung proton density at full expiration (r = 0.42 and 0.49), and lower lung clearance index (r = -0.50 and -0.41). After adjusting for MRI total proton density and BPD status, a 5% increase in forced expiratory volume at 1 s was associated with 738 (95% CI: 208, 1268) more steps per day and 0.1 (0.0, 0.2) more hours of MVPA, respectively. CONCLUSION: School-aged children born extremely preterm have similar physical activity levels to their peers, regardless of history of BPD. MRI and PFT measures suggestive of gas trapping and/or airflow obstruction are associated with lower physical activity levels.

Comparisons between umbilical cord biomarkers for newborn hypoxic-ischemic encephalopathy.

BACKGROUND: Cord blood umbilical artery (Ua) pH, base deficit (BD), and pH eucapnic Blickstein/Green-50 may mislead clinicians to identify newborns at risk for hypoxic-ischemic encephalopathy. Neonatal eucapnic pH (pH euc-n Racinet-54) may be a comprehensive alternative. The goal of the study is to compare the predictive performance of these four biomarkers for the combined primary outcome of hypoxic-ischemic encephalopathy/death. METHODS: This retrospective cohort study includes newborns ≥35 weeks gestational age. Receiver operating characteristics curves analysis was performed for Ua cord pH, BD, pH euc-n Racinet-54, and pH eucapnic Blickstein/Green-50 for the global cohort and for two subgroups of newborns with Ua cord pH ≤ 7.15. Cutoff values were derived for all four markers. RESULTS: From the original cohort of 61,037 newborns born between 1 January 2007 and 31 December 2016, we excluded cases with major congenital malformations and missing/incomplete data. The global cohort includes 51,286 newborns and 60 newborns afflicted with hypoxic-ischemic encephalopathy (HIE)/death. The area under the curves (AUC) derived from the global cohort were comparable between Ua cord pH (0.95; 95%CI = 0.94-0.95), BD (0.93; 95%CI = 0.93-0.93), pH euc-n Racinet-54 (0.93; 95% CI = 0.93-0.93), and lower for pH Blickstein/Green-50 (0.78; 95% CI = 0.77-0.78) (p < .05). Within newborn with severe acidemia (pH ≤ 7.00) and moderate acidemia (7.00 ≤ pH ≤ 7.15), pH euc-n Racinet-54 had the largest AUC and best positive likelihood ratios especially for sensitivity ≥ 0.80 to minimize false negative cases. CONCLUSION: In this large retrospective study, predictive performance for Ua cord pH, BD, and pH euc-n Racinet-54 are comparable when applied to the global group. For newborns with Ua cord pH ≤ 7.00 and Ua cord 7.00 ≤ pH ≤ 7.15, pH euc-n Racinet-54 appears better to identify those with HIE/death, especially when the target is sensitivity > 80%. Prospective studies will confirm if pH euc-n Racinet-54 is a better alternative to Ua cord pH and BD to evaluate newborn acid-base physiology.